HDF5 Release 1.4-Beta2 INTRODUCTION This document describes the differences between HDF5-1.2.0 and HDF5-1.4-Beta2, and contains information on the platforms tested and known problems in HDF5-1.4-Beta2. For more details check the HISTORY file in the HDF5 source. The HDF5 documentation can be found on the NCSA ftp server (ftp.ncsa.uiuc.edu) in the directory: /HDF/HDF5/docs/ For more information look at the HDF5 home page at: http://hdf.ncsa.uiuc.edu/HDF5/ If you have any questions or comments, please send them to: hdfhelp@ncsa.uiuc.edu CONTENTS - New Features - h4toh5 Utility - F90 Support - C++ Support - Bug Fixes since HDF5-1.2.0 - Platforms Tested - Known Problems New Features ============ * The Virtual File Layer, VFL, was added to replace the old file drivers. It also provides an API for user defined file drivers. * New features added to snapshots. Use 'snapshot help' to see a complete list of features. * Improved configure to detect if MPIO routines are available when parallel mode is requested. * Added Thread-Safe support. Phase I implemented. * Added data sieve buffering to raw data I/O path. This is enabled for all VFL drivers except the mpio & core drivers. Setting the sieve buffer size is controlled with the new API function, H5Pset_sieve_buf_size(), and retrieved with H5Pget_sieve_buf_size(). * Added new Virtual File Driver, Stream VFD, to send/receive entire HDF5 files via socket connections. * As parts of VFL, HDF-GASS and HDF-SRB are also added to this release. To find out details, please read INSTALL_VFL file. * Increased maximum number of dimensions for a dataset (H5S_MAX_RANK) from 31 to 32 to align with HDF4 & netCDF. * Added 'query' function to VFL drivers. Also added 'type' parameter to VFL 'read' & 'write' calls, so they are aware of the type of data being accessed in the file. Updated the VFL document also. * A new h4toh5 uitlity, to convert HDF4 files to analogous HDF5 files. * Added a new array datatype to the datatypes which can be created. Removed "array fields" from compound datatypes (use an array datatype instead). * Parallel HDF5 works correctly with mpich-1.2.1 on Solaris, SGI, Linux. h4toh5 Utility ============== The h4toh5 utility is a new utility that converts an HDF4 file to an HDF5 file. For details, see the document, "Mapping HDF4 Objects to HDF5 Objects": http://hdf.ncsa.uiuc.edu/HDF5/papers/H4-H5MappingGuidelines.pdf Known Limitations of the h4toh5 beta release --------------------------------------------- 1. Error Handling Error reporting is minimal. 2. String Datatype HDF4 has no 'string' type. String valued data are usually defined as an array of 'char' in HDF4. The h4toh5 utility will generally map these to HDF5 'String' types rather than array of char, with the following additional rules: * For the data of an HDF4 SDS, image, and palette, if the data is declared 'DFNT_CHAR8' it will be assumed to be integer and will be an H5T_INTEGER type. * For attributes of any HDF4 object, data of type 'DFNT_CHAR8' will be converted to an HDF5 'H5T_STRING' type. * For an HDF4 Vdata, it is difficult to determine whether data of type 'DFNT_CHAR8' is intended to be bytes or characters. The h4toh5 utility will consider them to be C characters, and will convert them to an HDF5 'H5T_STRING' type. 3. Compression, Chunking and External Storage Chunking is supported, but compression and external storage is not. An HDF4 object that uses chunking will be converted to an HDF5 file with analogous chunked storage. An HDF4 object that uses compression will be converted to an uncompressed HDF5 object. An HDF4 object that uses external storage will be converted to an HDF5 object without external storage. 4. Memory Use The beta version of the h4toh5 utility copies data from HDF4 objects in a single read followed by a single write to the HDF5 object. For large objects, this requires a very large amount of memory, which may be extremely slow or fail on some platforms. Note that a dataset that has only been partly written will be read completely, including uninitialized data, and all the data will be written to the HDF5 object. 5. Platforms The h4toh5 utility requires HDF5.1.4. The beta h4toh5 utility has been tested on Solaris 2.6, Solaris 2.5, Irix 6.5, HPUX 11.0, DEC Unix, FreeBSD, and Windows 2000. F90 Support =========== This is the first release of the HDF5 Library with fully integrated F90 API support. The Fortran Library is created when the --enable-fortran flag is specified during configuration. Not all F90 subroutines are implemented. Please refer to the HDF5 Reference Manual for more details. F90 APIs are available for the Solaris 2.6 and 2.7, Linux, DEC UNIX, T3E, J90 and O2K (64 bit option only) platforms. The Parallel version of the HDF5 F90 Library is supported on the O2K and T3E platforms. Changes since the last prototype release (July 2000) ---------------------------------------------------- * h5open_f and h5close_f must be called instead of h5init_types and h5close_types. * The following subroutines are no longer available: h5pset_xfer_f h5pget_xfer_f h5pset_mpi_f h5pget_mpi_f h5pset_stdio_f h5pget_stdio_f h5pset_sec2_f h5pget_sec2_f h5pset_core_f h5pget_core_f h5pset_family_f h5pget_family_f * The following functions have been added: h5pset_fapl_mpio_f h5pget_fapl_mpio_f h5pset_dxpl_mpio_f h5pget_dxpl_mpio_f * In the previous HDF5 F90 releases, the implementation of object references and dataset region references was not portable. This release introduces a portable implementation, but it also introduces changes to the read/write APIs that handle references. If object or dataset region references are written or read to/from an HDF5 file, h5dwrite_f and h5dread_f must use the extra parameter, n, for the buffer size: h5dwrite(read)_f(dset_id, mem_type_id, buf, n, hdferr, & ^^^ mem_space_id, file_space_id, xfer_prp) For other datatypes the APIs were not changed. C++ Support =========== This is the first release of the HDF5 Library with fully integrated C++ API support. The HDF5 C++ library is built when the --enable-cxx flag is specified during configuration. Check the HDF5 Reference Manual for available C++ documentation. C++ APIs are available for Solaris 2.6 and 2.7, Linux, and FreeBSD. Bug Fixes since HDF5-1.2.0 ========================== Library ------- * The function H5Pset_mpi is renamed as H5Pset_fapl_mpio. * Corrected a floating point number conversion error for the Cray J90 platform. The error did not convert the value 0.0 correctly. * Error was fixed which was not allowing dataset region references to have their regions retrieved correctly. * Corrected a bug that caused non-parallel file drivers to fail in the parallel version. * Added internal free-lists to reduce memory required by the library and H5garbage_collect API function * Fixed error in H5Giterate which was not updating the "index" parameter correctly. * Fixed error in hyperslab iteration which was not walking through the correct sequence of array elements if hyperslabs were staggered in a certain pattern * Fixed several other problems in hyperslab iteration code. * Fixed another H5Giterate bug which was causes groups with large numbers of objects in them to misbehave when the callback function returned non-zero values. * Changed return type of H5Aiterate and H5A_operator_t typedef to be herr_t, to align them with the dataset and group iterator functions. * Changed H5Screate_simple and H5Sset_extent_simple to not allow dimensions of size 0 with out the same dimension being unlimited. * QAK - 4/19/00 - Improved metadata hashing & caching algorithms to avoid many hash flushes and also remove some redundant I/O when moving metadata blocks in the file. * The "struct(opt)" type conversion function which gets invoked for certain compound datatype conversions was fixed for nested compound types. This required a small change in the datatype conversion function API. * Re-wrote lots of the hyperslab code to speed it up quite a bit. * Added bounded garbage collection for the free lists when they run out of memory and also added H5set_free_list_limits API call to allow users to put an upper limit on the amount of memory used for free lists. * Checked for non-existent or deleted objects when dereferencing one with object or region references and disallow dereference. * "Time" datatypes (H5T_UNIX_D*) were not being stored and retrieved from object headers correctly, fixed now. * Fixed H5Dread or H5Dwrite calls with H5FD_MPIO_COLLECTIVE requests that may hang because not all processes are transfer the same amount of data. (A.K.A. prematured collective return when zero amount data requested.) Collective calls that may cause hanging is done via the corresponding MPI-IO independent calls. Configuration ------------- * The hdf5.h include file was fixed to allow the HDF5 Library to be compiled with other libraries/applications that use GNU autoconf. * Configuration for parallel HDF5 was improved. Configure now attempts to link with libmpi.a and/or libmpio.a as the MPI libraries by default. It also uses "mpirun" to launch MPI tests by default. It tests to link MPIO routines during the configuration stage, rather than failing later as before. One can just do "./configure --enable-parallel" if the MPI library is in the system library. * Added support for pthread library and thread-safe option. * The libhdf5.settings file shows the correct machine byte-sex. * Added option "--enable-stream-vfd" to configure w/o the Stream VFD. For Solaris, added -lsocket to the LIBS list of libraries. Tools ----- * h5dump now accepts both short and long command-line parameters. A change from the old way is that multiple attributes, datasets, groups, soft-links, and object-ids cannot be specified with just one flag but you have to use a flag with each object. I.e., instead of doing this: h5dump -a /attr1 /attr2 foo.h5 do this: h5dump -a /attr1 -a /attr2 foo.h5 The cases are similar for the other object types. * h5dump correctly displays compound datatypes. * Corrected an error in h5toh4 which did not convert the 32bits int from HDF5 to HDF4 corectly for the T3E platform. * h5dump correctly displays the committed copy of predefined types correctly. * Added an option, -V, to show the version information of h5dump. * Fixed a core dumping bug of h5toh4 when executed on platforms like TFLOPS. * The test script for h5toh4 used to not able to detect the hdp dumper command was not valid. It now detects and reports the failure of hdp execution. * Merged the tools with the 1.2.2 branch. Required adding new macros, VERSION12 and VERSION13, used in conditional compilation. Updated the Windows project files for the tools. * h5dump displays opaque and bitfield data correctly. * h5dump and h5ls can browse files created with the Stream VFD (eg. "h5ls :"). * h5dump has a new feature "-o " which outputs the raw data of the dataset into ascii text file . * h5toh4 used to converts hdf5 strings type to hdf4 DFNT_INT8 type. Corrected to produce hdf4 DFNT_CHAR type instead. * h5dump and h5ls displays array data correctly. Documentation ------------- * User's Guide and Reference Manual were updated. See doc/html/PSandPDF/index.html for more details. Platforms Tested ================ Note: Due to the nature of the bug fixes, only static versions of the library and tools were tested. AIX 4.3.2 (IBM SP) mpcc_r 3.6.6 Cray T3E sn6711 2.0.539b Cray Standard C Version 6.3.0.2 Cray Fortran Version 3.4.0.2 FreeBSD 4.2-STABLE gcc 2.95.2 g++ 2.95.2 HP-UX B.10.20 HP C HP92453-01 A.10.32.30 HP-UX B.11.00 HP C HP92453-01 A.11.00.13 IRIX 6.5 MIPSpro cc 7.30 IRIX64 6.5 (64 & n32) MIPSpro cc 7.3.1m mpt.1.4.0.2 mpich-1.2.1 Linux 2.2.16-3smp gcc-2.95.2 g++ 2.95.2 pgf90 3.1-3 OSF1 V4.0 DEC-V5.2-040 Digital Fortran 90 V4.1-270 SunOS 5.6 WorkShop Compilers 5.0 98/12/15 C 5.0 (Solaris 2.6) WorkShop Compilers 5.0 99/10/25 Fortran 90 2.0 Patch 107356-04 Workshop Compilers 5.0 98/12/15 C++ 5.0 SunOS 5.7 WorkShop Compilers 5.0 98/12/15 C 5.0 (Solaris 2.7) WorkShop Compilers 5.0 99/10/25 Fortran 90 2.0 Patch 107356-04 Workshop Compilers 5.0 98/12/15 C++ 5.0 TFLOPS 3.3 mpich-1.2.0 with local changes Windows NT4.0, 2000 (NT5.0) MSVC++ 6.0 Known Problems ============== * When building the HDF5 test project on Windows NT 4.0 (testhdf5 and testhdf5dll), the compiler fails to compile tvstr.c within the whole project; however, when separately selecting the tvstr.c source code, it passes the compiler and everything that depends on tvstr.obj links correctly. * h4toh5 fails on object references on the Cray T3E. * The installation of the DEC Fortran binaries fails. It can be done manually by copying the *.mod files from the fortran/src directory. * Fortran modules are not installed when created. This should be done manually by copying the modules from the fortran/src directory. * SunOS 5.6 with C WorkShop Compilers 4.2: Hyperslab selections will fail if library is compiled using optimization of any level. * The Stream VFD was not tested yet under Windows. It is not supported in the TFLOPS machine. * Shared library option is broken for IBM SP and some Origin 2000 platforms. One needs to run ./configure with '--disable-shared' * The ./dsets tests failed in the TFLOPS machine if the test program, dsets.c, is compiled with the -O option. The hdf5 library still works correctly with the -O option. The test program works fine if it is compiled with -O1 or -O0. Only -O (same as -O2) causes the test program to fail. * Certain platforms give false negatives when testing h5ls: - Solaris x86 2.5.1, Cray T3E and Cray J90 give errors during testing when displaying object references in certain files. These are benign differences due to the difference in sizes of the objects created on those platforms. h5ls appears to be dumping object references correctly. - Cray J90 (and Cray T3E?) give errors during testing when displaying some floating-point values. These are benign differences due to the different precision in the values displayed and h5ls appears to be dumping floating-point numbers correctly.